[pve-devel] [PATCH pve-container 1/3] Cgroups: use base PVE::CGroup and keep specific lxc code
Alexandre Derumier
aderumier at odiso.com
Fri Oct 30 10:42:26 CET 2020
---
src/PVE/LXC/CGroup.pm | 532 +-----------------------------------------
1 file changed, 3 insertions(+), 529 deletions(-)
diff --git a/src/PVE/LXC/CGroup.pm b/src/PVE/LXC/CGroup.pm
index 6710843..19562c2 100644
--- a/src/PVE/LXC/CGroup.pm
+++ b/src/PVE/LXC/CGroup.pm
@@ -12,155 +12,10 @@ package PVE::LXC::CGroup;
use strict;
use warnings;
-use IO::File;
-use IO::Select;
-use POSIX qw();
-
-use PVE::ProcFSTools;
-use PVE::Tools qw(
- file_get_contents
- file_read_firstline
-);
-
use PVE::LXC::Command;
+use PVE::CGroup;
+use base('PVE::CGroup');
-# We don't want to do a command socket round trip for every cgroup read/write,
-# so any cgroup function needs to have the container's path cached, so this
-# package has to be instantiated.
-#
-# LXC keeps separate paths by controller (although they're normally all the
-# same, in our # case anyway), so we cache them by controller as well.
-sub new {
- my ($class, $vmid) = @_;
-
- my $self = { vmid => $vmid };
-
- return bless $self, $class;
-}
-
-# Get the v1 controller list.
-#
-# Returns a set (hash mapping names to `1`) of cgroupv1 controllers, and an
-# optional boolean whether a unified (cgroupv2) hierarchy exists.
-#
-# Deprecated: Use `get_cgroup_controllers()` instead.
-sub get_v1_controllers {
- my $v1 = {};
- my $v2 = 0;
- my $data = PVE::Tools::file_get_contents('/proc/self/cgroup');
- while ($data =~ /^\d+:([^:\n]*):.*$/gm) {
- my $type = $1;
- if (length($type)) {
- $v1->{$_} = 1 foreach split(/,/, $type);
- } else {
- $v2 = 1;
- }
- }
- return wantarray ? ($v1, $v2) : $v1;
-}
-
-# Get the set v2 controller list from the `cgroup.controllers` file.
-my sub get_v2_controllers {
- my $v2 = eval { file_get_contents('/sys/fs/cgroup/cgroup.controllers') }
- || eval { file_get_contents('/sys/fs/cgroup/unified/cgroup.controllers') };
- return undef if !defined $v2;
-
- # It's a simple space separated list:
- return { map { $_ => 1 } split(/\s+/, $v2) };
-}
-
-my $CGROUP_CONTROLLERS = undef;
-# Get a list of controllers enabled in each cgroup subsystem.
-#
-# This is a more complete version of `PVE::LXC::get_cgroup_subsystems`.
-#
-# Returns 2 sets (hashes mapping controller names to `1`), one for each cgroup
-# version.
-sub get_cgroup_controllers() {
- if (!defined($CGROUP_CONTROLLERS)) {
- my ($v1, undef) = get_v1_controllers();
- my $v2 = get_v2_controllers();
-
- $CGROUP_CONTROLLERS = [$v1, $v2];
- }
-
- return $CGROUP_CONTROLLERS->@*;
-}
-
-my $CGROUP_MODE = undef;
-# Figure out which cgroup mode we're operating under:
-#
-# Returns 1 if cgroupv1 controllers exist (hybrid or legacy mode), and 2 in a
-# cgroupv2-only environment.
-#
-# NOTE: To fully support a hybrid layout it is better to use functions like
-# `cpuset_controller_path`.
-#
-# This is a function, not a method!
-sub cgroup_mode() {
- if (!defined($CGROUP_MODE)) {
- my ($v1, $v2) = get_cgroup_controllers();
- if (keys %$v1) {
- # hybrid or legacy mode
- $CGROUP_MODE = 1;
- } elsif ($v2) {
- $CGROUP_MODE = 2;
- }
- }
-
- die "unknown cgroup mode\n" if !defined($CGROUP_MODE);
- return $CGROUP_MODE;
-}
-
-my $CGROUPV2_PATH = undef;
-sub cgroupv2_base_path() {
- if (!defined($CGROUPV2_PATH)) {
- if (cgroup_mode() == 2) {
- $CGROUPV2_PATH = '/sys/fs/cgroup';
- } else {
- $CGROUPV2_PATH = '/sys/fs/cgroup/unified';
- }
- }
- return $CGROUPV2_PATH;
-}
-
-# Find a cgroup controller and return its path and version.
-#
-# LXC initializes the unified hierarchy first, so if a controller is
-# available via both we favor cgroupv2 here as well.
-#
-# Returns nothing if the controller is not available.
-sub find_cgroup_controller($) {
- my ($controller) = @_;
-
- my ($v1, $v2) = get_cgroup_controllers();
-
- if (!defined($controller) || $v2->{$controller}) {
- my $path = cgroupv2_base_path();
- return wantarray ? ($path, 2) : $path;
- }
-
- if (defined($controller) && $v1->{$controller}) {
- my $path = "/sys/fs/cgroup/$controller";
- return wantarray ? ($path, 1) : $path;
- }
-
- return;
-}
-
-my $CG_PATH_CPUSET = undef;
-my $CG_VER_CPUSET = undef;
-# Find the cpuset cgroup controller.
-#
-# This is a function, not a method!
-sub cpuset_controller_path() {
- if (!defined($CG_PATH_CPUSET)) {
- ($CG_PATH_CPUSET, $CG_VER_CPUSET) = find_cgroup_controller('cpuset')
- or die "failed to find cpuset controller\n";
- }
-
- return wantarray ? ($CG_PATH_CPUSET, $CG_VER_CPUSET) : $CG_PATH_CPUSET;
-}
# Get a subdirectory (without the cgroup mount point) for a controller.
#
@@ -170,7 +25,7 @@ sub cpuset_controller_path() {
# (`cgroup.controllers` file) as list of controllers for the unified hierarchy,
# so this returns a result when a `controller` is provided even when using
# a pure cgroupv2 setup.
-my sub get_subdir {
+sub get_subdir {
my ($self, $controller, $limiting) = @_;
my $entry_name = $controller || 'unified';
@@ -198,385 +53,4 @@ my sub get_subdir {
return $path;
}
-# Get path and version for a controller.
-#
-# `$controller` may be `undef`, see get_subdir above for details.
-#
-# Returns either just the path, or the path and cgroup version as a tuple.
-sub get_path {
- my ($self, $controller, $limiting) = @_;
-
- # Find the controller before querying the lxc monitor via a socket:
- my ($cgpath, $ver) = find_cgroup_controller($controller)
- or return undef;
-
- my $path = get_subdir($self, $controller, $limiting)
- or return undef;
-
- $path = "$cgpath/$path";
- return wantarray ? ($path, $ver) : $path;
-}
-
-# Convenience method to get the path info if the first existing controller.
-#
-# Returns the same as `get_path`.
-sub get_any_path {
- my ($self, $limiting, @controllers) = @_;
-
- my ($path, $ver);
- for my $c (@controllers) {
- ($path, $ver) = $self->get_path($c, $limiting);
- last if defined $path;
- }
- return wantarray ? ($path, $ver) : $path;
-}
-
-# Parse a 'Nested keyed' file:
-#
-# See kernel documentation `admin-guide/cgroup-v2.rst` 4.1.
-my sub parse_nested_keyed_file($) {
- my ($data) = @_;
- my $res = {};
- foreach my $line (split(/\n/, $data)) {
- my ($key, @values) = split(/\s+/, $line);
-
- my $d = ($res->{$key} = {});
-
- foreach my $value (@values) {
- if (my ($key, $value) = ($value =~ /^([^=]+)=(.*)$/)) {
- $d->{$key} = $value;
- } else {
- warn "bad key=value pair in nested keyed file\n";
- }
- }
- }
- return $res;
-}
-
-# Parse a 'Flat keyed' file:
-#
-# See kernel documentation `admin-guide/cgroup-v2.rst` 4.1.
-my sub parse_flat_keyed_file($) {
- my ($data) = @_;
- my $res = {};
- foreach my $line (split(/\n/, $data)) {
- if (my ($key, $value) = ($line =~ /^(\S+)\s+(.*)$/)) {
- $res->{$key} = $value;
- } else {
- warn "bad 'key value' pair in flat keyed file\n";
- }
- }
- return $res;
-}
-
-# Parse out 'diskread' and 'diskwrite' values from I/O stats for this container.
-sub get_io_stats {
- my ($self) = @_;
-
- my $res = {
- diskread => 0,
- diskwrite => 0,
- };
-
- # With cgroupv1 we have a 'blkio' controller, with cgroupv2 it's just 'io':
- my ($path, $ver) = $self->get_any_path(1, 'io', 'blkio');
- if (!defined($path)) {
- # container not running
- return undef;
- } elsif ($ver == 2) {
- # cgroupv2 environment, io controller enabled
- my $io_stat = file_get_contents("$path/io.stat");
-
- my $data = parse_nested_keyed_file($io_stat);
- foreach my $dev (keys %$data) {
- my $dev = $data->{$dev};
- if (my $b = $dev->{rbytes}) {
- $res->{diskread} += $b;
- }
- if (my $b = $dev->{wbytes}) {
- $res->{diskread} += $b;
- }
- }
-
- return $res;
- } elsif ($ver == 1) {
- # cgroupv1 environment:
- my $io = file_get_contents("$path/blkio.throttle.io_service_bytes_recursive");
- foreach my $line (split(/\n/, $io)) {
- if (my ($type, $bytes) = ($line =~ /^\d+:\d+\s+(Read|Write)\s+(\d+)$/)) {
- $res->{diskread} += $bytes if $type eq 'Read';
- $res->{diskwrite} += $bytes if $type eq 'Write';
- }
- }
-
- return $res;
- } else {
- die "bad cgroup version: $ver\n";
- }
-
- # container not running
- return undef;
-}
-
-# Read utime and stime for this container from the cpuacct cgroup.
-# Values are in milliseconds!
-sub get_cpu_stat {
- my ($self) = @_;
-
- my $res = {
- utime => 0,
- stime => 0,
- };
-
- my ($path, $ver) = $self->get_any_path(1, 'cpuacct', 'cpu');
- if (!defined($path)) {
- # container not running
- return undef;
- } elsif ($ver == 2) {
- my $data = eval { file_get_contents("$path/cpu.stat") };
-
- # or no io controller available:
- return undef if !defined($data);
-
- $data = parse_flat_keyed_file($data);
- $res->{utime} = int($data->{user_usec} / 1000);
- $res->{stime} = int($data->{system_usec} / 1000);
- } elsif ($ver == 1) {
- # cgroupv1 environment:
- my $clock_ticks = POSIX::sysconf(&POSIX::_SC_CLK_TCK);
- my $clk_to_usec = 1000 / $clock_ticks;
-
- my $data = parse_flat_keyed_file(file_get_contents("$path/cpuacct.stat"));
- $res->{utime} = int($data->{user} * $clk_to_usec);
- $res->{stime} = int($data->{system} * $clk_to_usec);
- } else {
- die "bad cgroup version: $ver\n";
- }
-
- return $res;
-}
-
-# Parse some memory data from `memory.stat`
-sub get_memory_stat {
- my ($self) = @_;
-
- my $res = {
- mem => 0,
- swap => 0,
- };
-
- my ($path, $ver) = $self->get_path('memory', 1);
- if (!defined($path)) {
- # container most likely isn't running
- return undef;
- } elsif ($ver == 2) {
- my $mem = file_get_contents("$path/memory.current");
- my $swap = file_get_contents("$path/memory.swap.current");
-
- chomp ($mem, $swap);
-
- # FIXME: For the cgv1 equivalent of `total_cache` we may need to sum up
- # the values in `memory.stat`...
-
- $res->{mem} = $mem;
- $res->{swap} = $swap;
- } elsif ($ver == 1) {
- # cgroupv1 environment:
- my $stat = parse_flat_keyed_file(file_get_contents("$path/memory.stat"));
- my $mem = file_get_contents("$path/memory.usage_in_bytes");
- my $memsw = file_get_contents("$path/memory.memsw.usage_in_bytes");
- chomp ($mem, $memsw);
-
- $res->{mem} = $mem - $stat->{total_cache};
- $res->{swap} = $memsw - $mem;
- } else {
- die "bad cgroup version: $ver\n";
- }
-
- return $res;
-}
-
-# Change the memory limit for this container.
-#
-# Dies on error (including a not-running or currently-shutting-down guest).
-sub change_memory_limit {
- my ($self, $mem_bytes, $swap_bytes) = @_;
-
- my ($path, $ver) = $self->get_path('memory', 1);
- if (!defined($path)) {
- die "trying to change memory cgroup values: container not running\n";
- } elsif ($ver == 2) {
- PVE::ProcFSTools::write_proc_entry("$path/memory.swap.max", $swap_bytes)
- if defined($swap_bytes);
- PVE::ProcFSTools::write_proc_entry("$path/memory.max", $mem_bytes)
- if defined($mem_bytes);
- } elsif ($ver == 1) {
- # With cgroupv1 we cannot control memory and swap limits separately.
- # This also means that since the two values aren't independent, we need to handle
- # growing and shrinking separately.
- my $path_mem = "$path/memory.limit_in_bytes";
- my $path_memsw = "$path/memory.memsw.limit_in_bytes";
-
- my $old_mem_bytes = file_get_contents($path_mem);
- my $old_memsw_bytes = file_get_contents($path_memsw);
- chomp($old_mem_bytes, $old_memsw_bytes);
-
- $mem_bytes //= $old_mem_bytes;
- $swap_bytes //= $old_memsw_bytes - $old_mem_bytes;
- my $memsw_bytes = $mem_bytes + $swap_bytes;
-
- if ($memsw_bytes > $old_memsw_bytes) {
- # Growing the limit means growing the combined limit first, then pulling the
- # memory limitup.
- PVE::ProcFSTools::write_proc_entry($path_memsw, $memsw_bytes);
- PVE::ProcFSTools::write_proc_entry($path_mem, $mem_bytes);
- } else {
- # Shrinking means we first need to shrink the mem-only memsw cannot be
- # shrunk below it.
- PVE::ProcFSTools::write_proc_entry($path_mem, $mem_bytes);
- PVE::ProcFSTools::write_proc_entry($path_memsw, $memsw_bytes);
- }
- } else {
- die "bad cgroup version: $ver\n";
- }
-
- # return a truth value
- return 1;
-}
-
-# Change the cpu quota for a container.
-#
-# Dies on error (including a not-running or currently-shutting-down guest).
-sub change_cpu_quota {
- my ($self, $quota, $period) = @_;
-
- die "quota without period not allowed\n" if !defined($period) && defined($quota);
-
- my ($path, $ver) = $self->get_path('cpu', 1);
- if (!defined($path)) {
- die "trying to change cpu quota cgroup values: container not running\n";
- } elsif ($ver == 2) {
- # cgroupv2 environment, an undefined (unlimited) quota is defined as "max"
- # in this interface:
- $quota //= 'max'; # unlimited
- if (defined($quota)) {
- PVE::ProcFSTools::write_proc_entry("$path/cpu.max", "$quota $period");
- } else {
- # we're allowed to only write the quota:
- PVE::ProcFSTools::write_proc_entry("$path/cpu.max", 'max');
- }
- } elsif ($ver == 1) {
- $quota //= -1; # unlimited
- $period //= -1;
- PVE::ProcFSTools::write_proc_entry("$path/cpu.cfs_period_us", $period);
- PVE::ProcFSTools::write_proc_entry("$path/cpu.cfs_quota_us", $quota);
- } else {
- die "bad cgroup version: $ver\n";
- }
-
- # return a truth value
- return 1;
-}
-
-# Change the cpu "shares" for a container.
-#
-# In cgroupv1 we used a value in `[0..500000]` with a default of 1024.
-#
-# In cgroupv2 we do not have "shares", we have "weights" in the range
-# of `[1..10000]` with a default of 100.
-#
-# Since the default values don't match when scaling linearly, we use the
-# values we get as-is and simply error for values >10000 in cgroupv2.
-#
-# It is left to the user to figure this out for now.
-#
-# Dies on error (including a not-running or currently-shutting-down guest).
-sub change_cpu_shares {
- my ($self, $shares, $cgroupv1_default) = @_;
-
- my ($path, $ver) = $self->get_path('cpu', 1);
- if (!defined($path)) {
- die "trying to change cpu shares/weight cgroup values: container not running\n";
- } elsif ($ver == 2) {
- # the cgroupv2 documentation defines the default to 100
- $shares //= 100;
- die "cpu weight (shares) must be in range [1, 10000]\n" if $shares < 1 || $shares > 10000;
- PVE::ProcFSTools::write_proc_entry("$path/cpu.weight", $shares);
- } elsif ($ver == 1) {
- $shares //= 100;
- PVE::ProcFSTools::write_proc_entry("$path/cpu.shares", $shares // $cgroupv1_default);
- } else {
- die "bad cgroup version: $ver\n";
- }
-
- # return a truth value
- return 1;
-}
-
-my sub v1_freeze_thaw {
- my ($self, $controller_path, $freeze) = @_;
- my $path = get_subdir($self, 'freezer', 1)
- or die "trying to freeze container: container not running\n";
- $path = "$controller_path/$path/freezer.state";
-
- my $data = $freeze ? 'FROZEN' : 'THAWED';
- PVE::ProcFSTools::write_proc_entry($path, $data);
-
- # Here we just poll the freezer.state once per second.
- while (1) {
- my $state = file_get_contents($path);
- chomp $state;
- last if $state eq $data;
- }
-}
-
-my sub v2_freeze_thaw {
- my ($self, $controller_path, $freeze) = @_;
- my $path = get_subdir($self, undef, 1)
- or die "trying to freeze container: container not running\n";
- $path = "$controller_path/$path";
-
- my $desired_state = $freeze ? 1 : 0;
-
- # cgroupv2 supports poll events on cgroup.events which contains the frozen
- # state.
- my $fh = IO::File->new("$path/cgroup.events", 'r')
- or die "failed to open $path/cgroup.events file: $!\n";
- my $select = IO::Select->new();
- $select->add($fh);
-
- PVE::ProcFSTools::write_proc_entry("$path/cgroup.freeze", $desired_state);
- while (1) {
- my $data = do {
- local $/ = undef;
- <$fh>
- };
- $data = parse_flat_keyed_file($data);
- last if $data->{frozen} == $desired_state;
- my @handles = $select->has_exception();
- next if !@handles;
- seek($fh, 0, 0)
- or die "failed to rewind cgroup.events file: $!\n";
- }
-}
-
-# Freeze or unfreeze a container.
-#
-# This will freeze the container at its outer (limiting) cgroup path. We use
-# this instead of `lxc-freeze` as `lxc-freeze` from lxc4 will not be able to
-# fetch the cgroup path from contaienrs still running on lxc3.
-sub freeze_thaw {
- my ($self, $freeze) = @_;
-
- my $controller_path = find_cgroup_controller('freezer');
- if (defined($controller_path)) {
- return v1_freeze_thaw($self, $controller_path, $freeze);
- } else {
- # cgroupv2 always has a freezer, there can be both cgv1 and cgv2
- # freezers, but we'll prefer v1 when it's available as that's what lxc
- # does as well...
- return v2_freeze_thaw($self, cgroupv2_base_path(), $freeze);
- }
-}
-
1;
--
2.20.1
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